The

fallacy A fallacy is the use of invalid or otherwise faulty reasoning, or "wrong moves," in the construction of an argument which may appear stronger than it really is if the fallacy is not spotted. The term in the Western intellectual tradition was intr ...

of converse accident (also called reverse accident, destroying the exception, or ''a dicto secundum quid ad dictum simpliciter'') is an

informal fallacy Informal fallacies are a type of incorrect argument in natural language. The source of the error is not just due to the ''form'' of the argument, as is the case for formal fallacies, but can also be due to their ''content'' and ''context''. Fall ...

that can occur in a

statistical syllogism A statistical syllogism (or proportional syllogism or direct inference) is a non- deductive syllogism. It argues, using inductive reasoning, from a generalization true for the most part to a particular case. Introduction Statistical syllogisms may ...

(an argument based on a

generalization A generalization is a form of abstraction whereby common properties of specific instances are formulated as general concepts or claims. Generalizations posit the existence of a domain or set of elements, as well as one or more common character ...

) when a rule that applies only to an exceptional case is wrongly applied to all cases in general.

Overview

For example: :If we allow people with

glaucoma Glaucoma is a group of eye diseases that result in damage to the optic nerve (or retina) and cause vision loss. The most common type is open-angle (wide angle, chronic simple) glaucoma, in which the drainage angle for aqueous humor, fluid withi ...

to use

medical marijuana Medical cannabis, or medical marijuana (MMJ), is cannabis and cannabinoids that are prescribed by physicians for their patients. The use of cannabis as medicine has not been rigorously tested due to production and governmental restriction ...

, then everyone should be allowed to use marijuana. * People with glaucoma use

marijuana Cannabis, also known as marijuana among other names, is a psychoactive drug from the cannabis plant. Native to Central or South Asia, the cannabis plant has been used as a drug for both recreational and entheogenic purposes and in various t ...

. * People with

should be allowed to choose what substances they use. * Therefore, all people who use marijuana should be allowed to choose what substances they use. The inductive version of this fallacy is called

hasty generalization A faulty generalization is an informal fallacy wherein a conclusion is drawn about all or many instances of a phenomenon on the basis of one or a few instances of that phenomenon. It is similar to a proof by example in mathematics. It is an examp ...

. See

faulty generalization A faulty generalization is an informal fallacy wherein a conclusion is drawn about all or many instances of a phenomenon on the basis of one or a few instances of that phenomenon. It is similar to a proof by example in mathematics. It is an examp ...

. This fallacy is similar to the

slippery slope A slippery slope argument (SSA), in logic, critical thinking, political rhetoric, and caselaw, is an argument in which a party asserts that a relatively small first step leads to a chain of related events culminating in some significant (usually ...

, where the opposition claims that if a restricted action under debate is allowed, such as allowing people with glaucoma to use medical marijuana, then the action will by stages become acceptable in general, such as eventually everyone being allowed to use marijuana. The two arguments imply there is no difference between the exception and the rule, and in fact fallacious slippery slope arguments often use the converse accident to the contrary as the basis for the argument. However, a key difference between the two is the point and position being argued. The above argument using converse accident is an argument ''for'' full legal use of marijuana given that glaucoma patients use it. The argument based on the slippery slope argues ''against'' medicinal use of marijuana because it will lead to full use. The opposing kind of

dicto simpliciter ''Secundum quid'' (also called ''secundum quid et simpliciter'', meaning " hat is truein a certain respect and hat is trueabsolutely") is a type of informal fallacy that occurs when the arguer fails to recognize the difference between rules of th ...

accident An accident is an unintended, normally unwanted event that was not directly caused by humans. The term ''accident'' implies that nobody should be blamed, but the event may have been caused by unrecognized or unaddressed risks. Most researche ...

External links

Stephen's guide: Converse accident
Syllogistic fallacies {{logic-stub